Conventionally, the height of a vehicle varies depending on, for instance, a boarding state in terms, among other factors, of the number of occupants and the amount of cargo load, if any, in the vehicle. Changes in vehicle height are determined by changes in wheel height of the wheels with respect to the body. Therefore, vehicle height has been conventionally detected on the basis of the actual vehicle height, using vehicle height sensors that detect wheel height.
Patent document 1: Japanese Patent Application Publication No. 2005-225339